Building a PC That's Totally Silent

Our Executive Tech columnist tests a new computer case that virtually eliminates PC noise. Here's his report.
I wrote last week that the drone from PC fans is getting so loud in some offices that it's a serious work distraction. But a specialty manufacturing company announced a new kind of computer case in January that eliminates the need for fans and thereby eliminates almost all PC noise.

That company is Zalman Tech Co., a Korean firm that is known for its elaborate after-market heat sinks, silent power supplies, and near-silent CPU fans. The new case, which keeps its components cool without fans, is the TNN 300. The acronym stands for Totally No Noise.

I traveled to Los Angeles to interview executives at Zalman USA. I also purchased a fully loaded TNN 300 for testing in my offices. This week, I report to you on the results.

Assembling a Noiseless PC

Zalman TNN 300 PC case The TNN 300 (see photo) is about the size of a standard mini-tower PC. It accomodates microATX motherboards, which are widely used. But the similarity to an ordinary PC case ends there.

Every surface of the case is made of thick aluminum. The box is surrounded on all four sides by serrated aluminum plates that radiate heat generated by the system. The CPU, graphics board, power supply, and Northbridge motherboard interface are covered by pure copper heat sinks instead of being cooled by fans. These heat sinks, in turn, are attached directly to the outside plates, wicking heat away without a sound.

The TNN 300 I purchased was assembled for me by Cool Tech PC (, a computer store in a Portland, Ore., suburb that is the largest U.S. reseller of TNN cases. To inspect the components, I visited the store and interviewed general manager Jon Schoenborn, technical supervisor Pete Nickol, and sales manager Darin Rohatinsky.

If you want a silent PC, it turns out you can't just slap the hottest and fastest hardware into a TNN 300 and expect it to work. The experts at Cool Tech say they've experimented for months with Zalman's case and the earlier (and much larger and more expensive) TNN 500AF to find the right match of performance and quietness.

After much discussion, this is the system we decided to build:

Motherboard. While the TNN 300 can physically accept any microATX form factor, the mobo must be a model with built-in passive cooling and no obstacles that would prevent the heat sinks on the CPU and other components from being connected to the outside of the case. Zalman provides a diagram of incompatible motherboard features as well as a listing of compatible models.

"In the case of the MSI board we chose, there are large heat sinks on the VRM [voltage regulatory modules]," explains Nickol. These cool the motherboard's power converters, something that's often neglected. Many motherboards don't even provide holes to screw on VRM heat sinks if you wanted to. For my test system, we installed an MSI RS482M4-ILD motherboard, which supports up to 4GB of RAM. (I installed 1GB to start.)

CPU. To prevent the system's CPU from overheating in a regime of passive cooling (relying on heat sinks instead of fans), Zalman and Cool Tech state that a CPU that burns 70 watts of power or less must be used. This eliminates the absolutely fastest of today's CPUs, which are cherished by hardcore gamers. But it allows plenty of horsepower to satisfy the business computing needs of even the most demanding office workers. We selected a 64-bit AMD Athlon 3500 with a Venice core, which runs at 67 watts.

Video board. Due to similar concerns about overheating, Zalman specifies that video boards installed in a TNN 300 case should be no hotter than an nVidia GeForce 6600 or similar. This leaves out nVidia's faster 6800 and 7Series chips, but again this shouldn't concern normal business users. We installed an XFX PV-T43P-ND with 256MV of RAM. This is a graphics board based on the 6600 that supports up to two DVI monitors at 2048 x 1536 each.

In an interview in his Los Angeles office, Zalman product specialist Yo How Low said the 6600 line is recommended because home PC buyers sometimes use their computers in non-climate-controlled spaces that get as hot as 80 or 90 degrees F. (27-32 C.). In an air-conditioned office where the temperature never rises above 72 F., he said, a GeForce 6800 could safely be used in a TNN 300 case.

Cool Tech's Nickol disputes this, saying GeForce 6800 chips get very hot, even in an air-conditioned space. Myself, I'm sticking with the 6600 line for the best success with passive cooling.

Drives. The TNN series of cases should really be called the TNFN: Totally No Fan Noise. The heat sinks attached to the extrusions on the outside of the aluminum case do, in fact, produce no noise, since there are no fans. But any hard disks and CD-ROM drives that are operating in the case do produce detectable sounds.

Fortunately, quiet drives are available that stay well below 20 decibels, which is barely audible even in a quiet room. We selected Samsung's HD160JJ 160GB hard disk and Quiet Combo CD-RW/DVD drive.

Power supply. The TNN 300 comes with a 350-watt power supply that is completely fanless. This provides plenty of power for whatever you might need to put into a PC such as this. The Zalman design is innovative, with an unusually flat power supply unit that lies tightly against one side of the case. Like the other components, heat pipes run from the PSU to the external serrated plates to dissipate heat.

Remote control. Although this feature can't be customized, the remote control on the TNN 300 is worth mentioning. A smoked piece of glass, which is almost invisible on the black outer surface of the case, allows you to control the PC and even turn it on and off from a distance. Since one major use for silent PC systems is in home entertainment, the ability to run the TNN 300 remotely is a nice touch.

As I mentioned last week, all that solid metal pushes the street price of the TNN 300 to about $700 for the case alone. This helped my test unit top the $2,000 mark when all the other components were installed.

In return, you receive a relatively powerful PC that won't add a constant roar to the side of your desk. In my offices, which are pretty quiet, you can't hear the TNN 300's disk drives operating unless you put your ears close to the case. Even a whole room filled with these little boxes would hardly be irritating to anyone.


If money is no object, the TNN 300 provides a computing experience of near total silence. For environments that need a reasonable amount of computing power, but can't tolerate the whine of PC fans -- such as audio labs, libraries, and home entertainment centers -- the expense could be well worth it.

The added price of the case, however, has held down its sales. Zalman's Low informed me that I now own one of only 1,500 TNN 300 cases that have so far been manufactured in the world. Zalman's Korean manufacturing plant, however, can be ramped up to produce as many as needed, he assured me, in case any corporations decide to place orders for a few thousand.

If the TNN 300 is too rich for your budget, you do have alternatives that can quiet your existing PCs for much less. I'll describe those options in this space next week.

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